The present invention is directed to a novel valve used to remove a sample from a main line flow of fluid. More specifically, the present invention is directed to a novel sample valve which can remove a sample of fluid from a main line flow thereof without fluid being adversely emitted into the atmosphere and without creating excessive amounts of waste.
It is often necessary to take a sample of fluid from a main line fluid flow for testing, for example, to determine product quality such as to ascertain the levels of impurities and to quantify impurities, and to run quantitative analyses of product such as concentration, pH, etc. Samples are typically taken by diverting a small sample stream from the main line flow and directing same to a sample container and the like. For example, a T-connector has been included in a main line flow and used to divert a fluid sample to a valve which could be opened to direct a portion of the diverted fluid to a sample container or the like. Unfortunately, when taking fluid samples out of substantially continuous processing systems, there typically is removed excess fluid creating waste and, as well, there are often atmospheric emissions associated with the sampling process, in particular, when the sample container or the like is brought off-line. Thus, unsampled fluid remaining in the T-connector between the main line flow and the sample valve is excess which is often simply dumped from the system. If toxic, this waste can poison the environment in which it has been disposed. Stagnate fluid may also pose problems of corrosion or leakage, etc. Accordingly, the process of taking a sample from a main fluid flow is often uneconomical due to the waste which is formed and importantly, due to the substantial costs which accrue to prevent the occurrence of health and safety hazards which may be generated by atmospheric emissions of sampled fluid associated with the sampling process or assuage the consequences of such hazards.
An example of a valve which is used to take samples from a main line flow is disclosed in U.S. Pat. No. 4,281,935, issued Aug. 4, 1981. The valve disclosed in this patent comprises an inlet and an outlet for a main line fluid flow path through the valve and a valve stem which passes through the main flow and can be seated on a valve seat which extends into the main flow. The valve seat includes a passage communicating with the main flow and a passage out through a separate portion of the valve. The valve is disclosed as being primarily useful for injecting a fluid into the main flow path via the passage in the valve seat but, the patent also discloses that the valve may be used to remove sample material from the main flow path by applying a vacuum at the separate valve outlet which communicates with the passage in the valve seat. This patent, however, does not remotely disclose the problems with respect to sample waste and environmental emissions of sampled fluid generated during the sampling process and accordingly, does not disclose a particular valve structure which may offer a solution to the problems addressed above.
Accordingly, a primary objective of the present invention is to provide a means for removing a sample from a fluid stream in an environmentally safe manner.
Another objective of the present invention is to provide a sample valve which can remove a small sample of a fluid from a main line fluid flow in an economical and environmentally safe manner in which atmospheric emissions from the diverted sample are avoided.
Still another object of the present invention is to provide a sample valve which is easy to manufacture and operate for removing a sample of fluid from a main line flow and which ensures the avoidance of emissions of the sampled fluid into the surrounding environment.
Yet another object of the invention is to provide a process for taking a sample of fluid from a substantially continuous main line fluid flow in an economical and environmentally safe manner.